Membranissa

Membranissa is a genus of fungi belonging to the family Tricholomataceae, commonly known as the mushroom family. The name *Membranissa* derives from the Latin word *membrana*, meaning "membrane," in reference to the delicate, web-like veil that often covers the gills of these mushrooms when young. This veil is a distinguishing characteristic of the genus.

Species within the genus *Membranissa* are typically found in temperate and subtropical regions worldwide, often growing in woodlands, forests, and grassy areas. They are saprotrophic, meaning they decompose organic matter, and are frequently associated with decaying wood or leaf litter. The most well-known species is *Membranissa hemichrysa*, commonly referred to as the "yellow-staining agaric" or "membranous mushroom."

Membranissa mushrooms have a slender, fragile cap that ranges from convex to flat with age, usually measuring between 2 to 6 centimeters in diameter. The cap surface is often smooth or slightly scaly, and its color varies from pale yellow to brownish hues. The gills are closely spaced and adnate (attached to the stem without a free edge), often staining yellow when bruised or handled. The stem is slender, fibrous, and may exhibit a slight bulbous base.

While some species of *Membranissa* are considered edible, they are generally not highly prized due to their small size and delicate texture. However, they are sometimes collected for culinary use in certain regions. Identification of *Membranissa* species should be approached with caution, as some look-alikes may be toxic or inedible. Proper field guides, mycological expertise, or molecular analysis are recommended for accurate identification.

Membranissa fungi play an ecological role in breaking down organic material, contributing to nutrient cycling in forest ecosystems. Their study also provides insights into fungal taxonomy, morphology, and evolutionary relationships within the Agaricales order.